Until 2002, the biggest challenge that lift manufacturers faced with were the lack of standards that would otherwise allow various lift components from different manufacturers to be assembled as part of a complete lift system. Since CAN has been popular during that time as a common field-bus mechanism, several lift component manufacturers adopted another standard higher layer protocol CANopen, that would allow for plug-and-play interconnection of lift components. Different component manufacturers were using their own proprietary protocol and standardization based upon CANopen was needed to achieve cross-manufacturer compatibility between lift component devices.
Elevator industry manufacturers had their initial meetings during 2001 – 2002 to create a CANopen based standardization for lift technologies that would allow interoperability and compatibility between various lift control devices. The CANopen Special Interest Group (SIG) Lift Control Systems, a technical working group of CiA, was assigned the task for finding a specification out of various CiA profiles that would suit the lift industry for interoperability and compatibility. In 2002, the Lift Control Systems SIG specified CiA 417 – known as the CANopen application profile for lift control systems. CiA 417 provides CANopen based specifications for the standardization of the component protocols from different manufacturers. Thus CiA 417 or CANopen Lift facilitated use of same field bus and compatibility between devices of different component manufacturers and suppliers in lift industry.
CANopen Lift and Virtual Devices Concept
The application profile defines device functions that are required to build a lift control system as well as the communication between these devices. These device functions are achieved through devices that are part of the lift control system. All the device functions could not be realized through separate physical devices and hence the concept of combination of several virtual devices per physical device is used. The virtual devices are those that constitute a complete lift system and include the input/output panel units, a car door unit, a car controller unit, a car drive unit, a car drive controller, a car position unit, a load measuring unit, a sensor unit, etc. The manufacturer can choose which functionalities they want in their physical device and specify only the needed virtual devices that should be integrated into the physical device. The system designer should ensure that all the virtual devices are present in his system. The application profile also defines the communication relationship (communication interfaces) for the virtual devices. That is, it defines the content and the behavior (the parameters, commands and services) of the Process Data Objects (PDO).
The CiA 417 comprises of 4 parts:
The virtual device concept also implements interoperability due to their implementation-independence. CANopen Lift provides system designers with the flexibility to select CiA 417 compliant devices from different manufacturers and integrate them into the lift control system without much difficulty.
CANopen Lift - Components and Compatibility
In order to meet the objective of a standardized specification that allows compatible lift control devices, the manufacturers of CANopen Lift components frequently perform compatibility checks for their products. It is under the leadership of various manufacturer-neutral working groups and CiA that compatibility tests are performed on a regular basis. Various industrial fests, fares and events are conducted for these compatibility and standardization tests as well as for demonstrating various CANopen Lift compliant products.
The current public version of CANopen Lift standard, version 2.0 is established since December 2009 and regular PlugFests are conducted to test the interoperability and compatibility of various CANopen Lift products. Starting from the first CANopen Lift PlugFest on March 2009, manufacturers and suppliers of controllers and lift components have been proving their devices’ compatibility and adhesion to the standard during the PlugFests.
The standard is further developed and extended and now it is on version 2.3 with many advanced features like energy consumption measurement, energy reduction commands, start and stop acceleration, etc. CiA has formed the Marketing Group Lift (MG Lift) for marketing the usage of the CiA 417 and to represent the standard and the products in various trade fairs and industrial events. They constructed the CANopen Lift Demonstrator in 2008 to demonstrate the standard and technology that unifies the working of various CANopen Lift components. Due to its modularity and flexibility, it can be assembled to simulate individual elevators and to test the compatibility between components of different manufacturers. Interlift is a biannual tradeshow being conducted at Augsburg, Germany for demonstrating the interoperability between CANopen Lift (CiA 417) based devises. The CANopen Lift Demonstrator has been presented at Interlift by CiA since 2009. Manufacturers and suppliers from different parts of the world are implementing CANopen Lift specifications to produce compatible products and their numbers are growing.
Advantages of CANopen Lift Technology
CANopen Lift offers numerous technical advantages in integration and diagnosis of lift control systems. Apart from these, it offers advantages like:
- Improved start-up.
- Easy diagnosis and debugging.
- Optimized speed and precise control of the equipment.
- Facility for preventive maintenance.
- Energy savings and control.
- It is possible to read measurement data for drive energy consumption over the CAN network.
- Increased data security and system availability.
- Remote maintenance and configuration of system through internet.
CANopen Lift in Industry
Böhnke & Partner has manufactured various lift control components that are CANopen Lift compliant. These include the Elevator position system USP, Door locks with false lock protection, Elevator control module bp408, etc. IXXAT is also providing various CANopen Lift applications. Safeline has its Lift controller compatible with any CANopen Lift network. Weber LiftTechnik Gmbh has the WE1 lift control system compatible with CANopen Lift components.